The (false) belief that large, innovative software designs can be
completely specified in advance and then painlessly magicked out of the
void by the normal efforts of a team of normally talented programmers. In
fact, experience has shown repeatedly that good designs arise only from
evolutionary, exploratory interaction between one (or at most a small
handful of) exceptionally able designer(s) and an active user population
— and that the first try at a big new idea is always wrong.
Unfortunately, because these truths don't fit the planning models beloved
of management, they are generally ignored.